.button-size(@padding; @font-size; @border-radius) {
  padding: @padding;
  font-size: @font-size;
  border-radius: @border-radius;
}

.button-color(@color; @background; @border) {
  color: @color;
  background-color: @background;
  border-color: @border;
  // a inside Button which only work in Chrome
  // http://stackoverflow.com/a/17253457
  > a:only-child {
    color: currentColor;

    &:after {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      bottom: 0;
      right: 0;
      background: transparent;
    }
  }
}

.button-variant(@color; @background; @border) {
  .button-color(@color; @background; @border);

  &:hover
    //&:focus
  {
    .button-color(tint(@color, 20%); tint(@background, 20%); tint(@border, 20%));
  }
  &:active,
  &.active {
    .button-color(shade(@color, 5%); shade(@background, 5%); shade(@background, 5%));
  }

  &.disabled,
  &[disabled],
  fieldset[disabled] & {
    &,
    &:hover,
    &:focus,
    &:active,
    &.active {
      .button-color(@btn-disable-color; @btn-disable-bg; @btn-disable-border);
    }
  }
}

.button-group-base(@btnClassName) {
  position: relative;
  display: inline-block;
  vertical-align: middle;
  > .@{btnClassName} {
    position: relative;
    float: left;

    &:hover,
      //&:focus,
    &:active,
    &.active {
      z-index: 2;
    }
  }

  & .@{btnClassName}-icon-only .oolong-icon {
    font-size: 14px;
    position: relative;
    top: 1px;
  }

  &-large .@{btnClassName}-icon-only .oolong-icon {
    font-size: 16px;
    top: 2px;
  }

  &-small .@{btnClassName}-icon-only .oolong-icon {
    font-size: 12px;
    top: 0;
  }

  &-circle .@{btnClassName} {
    border-radius: @btn-circle-size;
  }

  // size
  &-large&-circle .@{btnClassName} {
    border-radius: @btn-circle-size-large;
  }
  &-large {
    & > .@{btnClassName} {
      .button-size(@btn-padding-large; @btn-font-size-large; @btn-border-radius);
    }
  }

  &-small&-circle .@{btnClassName} {
    border-radius: @btn-circle-size-small;
  }
  &-small {
    & > .@{btnClassName} {
      .button-size(@btn-padding-small; @btn-font-size; @btn-border-radius-small);

      > .@{css-prefix-iconfont} {
        font-size: @btn-font-size;
      }
    }
  }
}

.button-group-vertical-base(@btnClassName) {
  display: inline-block;
  vertical-align: middle;
  > .@{btnClassName} {
    display: block;
    width: 100%;
    max-width: 100%;
    float: none;
  }
}

.btn() {
  display: inline-block;
  margin-bottom: 0;
  font-weight: @btn-font-weight;
  text-align: center;
  vertical-align: middle;
  touch-action: manipulation;
  cursor: pointer;
  background-image: none;
  border: 1px solid transparent;
  white-space: nowrap;
  line-height: @line-height-base;
  user-select: none;
  .button-size(@btn-padding-base; @btn-font-size; @btn-border-radius);
  //transform: translate3d(0, 0, 0);
  //transition: all @transition-time linear;
  transition: color @transition-time linear, background-color @transition-time linear, border @transition-time linear, box-shadow @transition-time linear;

  > .@{css-prefix-iconfont} {
    line-height: 1;
  }

  &,
  &:active,
  &:focus {
    outline: 0;
  }

  &:not([disabled]):hover {
    text-decoration: none;
  }

  &:not([disabled]):active {
    outline: 0;
    // transition: none;  // 如果不注释此行，那么active会和focus同时触发，此时focus的开始动画transition会无效
  }

  &.disabled,
  &[disabled] {
    cursor: @cursor-disabled;

    > * {
      pointer-events: none;
    }
  }

  &-large {
    .button-size(@btn-padding-large; @btn-font-size-large; @btn-border-radius);
  }

  &-small {
    .button-size(@btn-padding-small; @btn-font-size; @btn-border-radius-small);
  }
}

// Default
.btn-default() {
  .button-variant(@btn-default-color; @btn-default-bg; @btn-default-border);

  &:hover
    //&:focus
  {
    .button-color(tint(@primary-color, 20%); white; tint(@primary-color, 20%));
  }
  &:active,
  &.active {
    .button-color(shade(@primary-color, 5%); white; shade(@primary-color, 5%));
  }
  .active-btn-color(@primary-color);
}

// Primary
.btn-primary() {
  .button-variant(@btn-primary-color; @btn-primary-bg; @primary-color);

  &:hover,
    //&:focus,
  &:active,
  &.active {
    color: @btn-primary-color;
  }
  .active-btn-color(@primary-color);
}

// Ghost
.btn-ghost() {
  .button-variant(@btn-ghost-color, @btn-ghost-bg, @btn-ghost-border);

  &:hover
    //&:focus
  {
    .button-color(tint(@primary-color, 20%); @btn-ghost-bg; tint(@primary-color, 20%));
  }
  &:active,
  &.active {
    .button-color(shade(@primary-color, 5%); @btn-ghost-bg; shade(@primary-color, 5%));
  }
  .active-btn-color(@primary-color);
}

// Dashed
.btn-dashed() {
  .button-variant(@btn-ghost-color, @btn-ghost-bg, @btn-ghost-border);
  border-style: dashed;

  &:hover
    //&:focus
  {
    .button-color(tint(@primary-color, 20%); @btn-ghost-bg; tint(@primary-color, 20%));
  }
  &:active,
  &.active {
    .button-color(shade(@primary-color, 5%); @btn-ghost-bg; shade(@primary-color, 5%));
  }
  .active-btn-color(@primary-color);
}

// Text
.btn-text() {
  .button-variant(@btn-ghost-color, @btn-ghost-bg, transparent);

  // for disabled
  &.disabled,
  &[disabled],
  fieldset[disabled] & {
    &,
    &:hover,
    &:focus,
    &:active,
    &.active {
      .button-color(@btn-disable-color; @btn-ghost-bg; transparent);
    }
  }

  &:hover
    //&:focus
  {
    .button-color(tint(@primary-color, 20%); @btn-ghost-bg; transparent);
  }
  &:active,
  &.active {
    .button-color(shade(@primary-color, 5%); @btn-ghost-bg; transparent);
  }
  .active-btn-color(@primary-color);
}

// Color
// for tabindex
.active-btn-color(@color) {
  &:focus {
    box-shadow: 0 0 0 2px fade(@color, 20%);
  }
}

.btn-color(@color) {
  .button-variant(@btn-primary-color; @color; @color);

  &:hover,
    //&:focus,
  &:active,
  &.active {
    color: @btn-primary-color;
  }

  .active-btn-color(@color);
}

// Circle for Icon
.btn-circle(@btnClassName: oolong-btn) {
  border-radius: @btn-circle-size;

  &.@{btnClassName}-large {
    border-radius: @btn-circle-size-large;
  }

  &.@{btnClassName}-size {
    border-radius: @btn-circle-size-small;
  }

  &.@{btnClassName}-icon-only {
    .square(@btn-circle-size);
    .button-size(0; @font-size-base + 2; 50%);

    &.@{btnClassName}-large {
      .square(@btn-circle-size-large);
      .button-size(0; @btn-font-size-large + 2; 50%);
    }

    &.@{btnClassName}-small {
      .square(@btn-circle-size-small);
      .button-size(0; @font-size-base; 50%);
    }
  }
}

// Group
.btn-group(@btnClassName: oolong-btn) {
  .button-group-base(@btnClassName);

  .@{btnClassName} + .@{btnClassName},
  .@{btnClassName} + &,
  & + .@{btnClassName},
  & + & {
    margin-left: -1px;
  }

  .@{btnClassName}:not(:first-child):not(:last-child) {
    border-radius: 0;
  }

  &:not(&-vertical) > .@{btnClassName}:first-child {
    margin-left: 0;

    &:not(:last-child) {
      border-bottom-right-radius: 0;
      border-top-right-radius: 0;
    }
  }

  &:not(&-vertical) > .@{btnClassName}:last-child:not(:first-child) {
    border-bottom-left-radius: 0;
    border-top-left-radius: 0;
  }

  & > & {
    float: left;
  }

  & > &:not(:first-child):not(:last-child) > .@{btnClassName} {
    border-radius: 0;
  }

  &:not(&-vertical) > &:first-child:not(:last-child) {
    > .@{btnClassName}:last-child {
      border-bottom-right-radius: 0;
      border-top-right-radius: 0;
      padding-right: 8px;
    }
  }

  &:not(&-vertical) > &:last-child:not(:first-child) > .@{btnClassName}:first-child {
    border-bottom-left-radius: 0;
    border-top-left-radius: 0;
    padding-left: 8px;
  }
}

.btn-group-vertical(@btnClassName: oolong-btn) {
  .button-group-vertical-base(@btnClassName);

  .@{btnClassName} + .@{btnClassName},
  .@{btnClassName} + &,
  & + .@{btnClassName},
  & + & {
    margin-top: -1px;
    margin-left: 0px;
  }

  > .@{btnClassName}:first-child {
    margin-top: 0;

    &:not(:last-child) {
      border-bottom-left-radius: 0;
      border-bottom-right-radius: 0;
    }
  }

  > .@{btnClassName}:last-child:not(:first-child) {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
  }

  & > &:first-child:not(:last-child) {
    > .@{btnClassName}:last-child {
      border-bottom-left-radius: 0;
      border-bottom-right-radius: 0;
      padding-bottom: 8px;
    }
  }

  & > &:last-child:not(:first-child) > .@{btnClassName}:first-child {
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
    padding-top: 8px;
  }
}
